distinct values in sql?

distinct values in sql?

I need an sql query to count the number of distinct occurrences of the
numbers 2, 5, 7, & 9 in the left hand column (table below).
I have played w DISTINCT and COUNT. Need a query to show how many of each
value there are.
I know there's a bone-head simple solution to this, just cant figure it
out. Thanks!
CLASS_ID STUDENT_ID



2 12
2 11
2 2
2 7
2 8
2 16
2 21
7 10
7 2
7 3
7 4
7 5
7 6
7 7
7 8
7 9
9 2
9 11
9 12
9 13
9 14
9 15
9 16
9 17
9 18
9 20
9 21
9 22
10 12
10 4
10 3
10 6
10 8
10 9
10 12
10 16
10 18
10 20
10 2
10 4